PMID: 28508504

Authors:

Bock T, Luxenburger E, Hoffmann J, Schutza V, Feiler C, Muller R, Blankenfeldt W

Title:

AibA/AibB Induces an Intramolecular Decarboxylation in Isovalerate Biosynthesis by Myxococcus xanthus.

Journal:

Angew Chem Int Ed Engl. 2017 Aug 7;56(33):9986-9989. doi: 10.1002/anie.201701992., Epub 2017 May 16.

Abstract:

Isovaleryl coenzyme A (IV-CoA) is an important precursor for iso-fatty acids and lipids. It acts in the development of myxobacteria, which can produce this compound from acetyl-CoA through alternative IV-CoA biosynthesis (aib). A central reaction of aib is catalyzed by AibA/AibB, which acts as a cofactor-free decarboxylase despite belonging to the family of CoA-transferases. We developed an efficient expression system for AibA/AibB that allowed the determination of high-resolution crystal structures in complex with different ligands. Through mutational studies, we show that an active-site cysteine previously proposed to be involved in decarboxylation is not required for activity. Instead, AibA/AibB seems to induce an intramolecular decarboxylation by binding its substrate in a hydrophobic cavity and forcing it into a bent conformation. Our study opens opportunities for synthetic biology studies, since AibA/AibB may be suitable for the production of isobutene, a precursor of biofuels and chemicals.